Throw-off mechanism for rotary offset presses



Sept. 21, 1954 J. R. woon 2,689,524

THROW-OFF MECHANISM FOR ROTARY OFFSET PRESSES Original Filed Aug. 26, 1948 5 Sheets-Sheet l INVENTOR. $4045: A. 14/090 BY' flrroelveys J. R. WOOD Sept. 21, 1954 THROW-OFF MECHANISM FOR ROTARY OFFSET PRESSES Original Filed Aug. 26, 1948 5 Sheets-Sheet 2 INVENTOR.

JhMe-s A? 14 000 J. R. WOOD THROW-OFF MECHANISM FOR ROTARY OFFSET PRESSES 7 Original Filed Aug. 26, 1948 5 Sheets-Sheet 5 INVENTOR. JIMES A. W000 J. R. WOOD Sept. 21, 1954 THROW-OFF MECHANISM FOR ROTARY OFFSET PRESSES Original Filed Aug. 26, 1948 5 Sheds-Sheet 4 in l-l-l l INVENTOR. Jmvss A? W000 BY I mwpwt da 2/ .O

rmzvsya v Sept. 21, 1954 J. R. WOOD THROW-OFF MECHANISM FOR ROTARY OFFSET PRESSES Original Filed Aug. 26, 1948 5 Shee t BY Mg;

s-Sheet 5 INVENTOR. J2me: A. W000 Patented Sept. 21, 1954 THROW-OFF MECHANISM FOR ROTARY OFFSET PRESSES James R. Wood, Cleveland, Ohio Continuation of abandoned application Serial No.

46,298, August 26, 1948. This application November 14, 1951, Serial No. 256,244

13 Claims. 1

This invention relates to improvements in throwoff mechanism for rotary offset press, and has to do particularly with throwoif mechanism for rotary offset printing presses in which tripping of the press causes movement of the blanket cylinder toward or from the plate cylinder and the impression cylinder sequentially.

This application is a continuation of my copending application Serial No. 46,298 filed August 26, 1948, and now abandoned.

One of the objects of the invention is the provision of means for accomplishing such sequential operation smoothly and without undue friction.

Another object is the provision of mechanism for this purpose wherein the shaft of the blanket cylinder is mounted in a pair of eccentrics which are in turn mounted in movable bearing blocks with mechanism for actuating the eccentrics first to throw off the blanket cylinder from the plate cylinder and thereafter in the same cycle of the press unit for moving the bearing blocks to throw off the blanket cylinder from the impression cylinder, the same mechanism functioning in the same sequence when impression is to be thrown on, namely to throw the blanket cylinder against the plate cylinder first and against the impression cylinder thereafter.

Other objects and features of novelty will appear as I proceed with the description of that embodiment of the invention which, for the purposes of the present application, I have illustrated in the accompanying drawings, in which Fig. 1 is a side elevational view,more or less diagrammatic in character, of a unit of a rotary offset printing press embodying the invention, with the cylinders in printing relation.

Fig. 2 is a similar view with the blanket cylinder thrown off from the plate cylinder.

Fig. 3 is a similar view with the blanket cylinder thrown off from both the plate and the impression cylinders.

Fig. 4 is a detail plan view of an adjusting means for the mechanism employed to move the bearing blocks.

Fig. 5 is a detail sectional view taken substantially on the line 55 of Fig. 1.

Fig. 6 is a detail elevational view of an adjustable thrust block which may be employed in connection with the invention.

Fig. 7 is a side view of the same, and

Fig. 8 is a sectional view taken substantially along the line 88 of Fig. 6

Referring to the drawings one side member of a press frame is shown fragmentally at II]. In

this and the opposite side member, not shown, are journaled the shafts II and I2 of the plate and impression cylinders I3 and I4 of a unit of a rotary offset printing press. These cylinders therefore have fixed axes. The blanket cylinder I5 has bearings that are movable first away from cylinder I3 and secondly away from cylinder I4, the throwoif being accomplished sequentially and occurring in each instance while the gaps in the cylinders are passing each other.

At the opposite ends of the blanket cylinder the side frame members are cut away as indicated at I6, and in these openings are oscillatably mounted a pair of like bearing blocks, one of which is shown at I! in the drawings. The lower end of each of these blocks has a transverse recess I8 of cylindrical contour in which is mounted a bearing pin I9, this pin being secured to the block by a pair of screws 29 which are set into counterbored holes in the pin. A pair of bearing caps 2I secured to the frame by screws 22 hold pin I9 in a cavity 23 of cylindrical contour formed in each of the frame side members. When the block I1 is tilted therefore pin I9 turns in cavity 23 as a hearing. A heavy coil spring 24 bears at one end against an adjustable abutment 25 mounted in the frame and at the other end against an ear 26 which extends upwardly from the bearing block H. The spring therefore tends to swing the bearing block counterclockwise upon its bearing I9, 23.

The aligned pivot pins I9 for the bearing blocks i! are located substantially in the plane through the axes of cylinders I3 and I5 on the side of cylinder I5 which is remote from cylinder I3. The opening I6 in each of the frame side members is closed by a bracket I2II which is removably attached to the frame by bolts I2I and I22.

It will be apparent that by removing the screws 22 and the caps 2 I, the bearing blocks I1 together with the eccentrics 28 mounted therein and the shaft bearings 30 carried by the eccentrics may be withdrawn axially of the cylinder shaft 3i out of the frame I0. When both bearing blocks have been thus removed and the brackets I20 have also been removed the blanket cylinder can be taken out of the machine for conditioning or replacement.

In each of the blocks I'I there is a circular opening 21 in which is mounted an eccentric 28. The circular opening 21 has its center at 29, which therefore is the center of rotation for eccentrics 28. Within each of the eccentrics 28 there is mounted the outer race. 39 of a roller bearing, the imier race of which carries the shaft 3! of blanket cylinder [5. A suitable bearing cap 32 may be attached to the eccentric 28 as shown in Fig. 5.

On the upper side of each eccentric 28 there is an outwardly extending bifurcated ear 33 in which is rotatably mounted a pin 34. A link 35 is adjustably connected with this pin. An eye on one end of link 35 is pivotally connected at 36 with a bifurcated crank 31 that is formed integrally with a yoke 38 which is keyed to a shaft 39 that is mounted in the frame and extends entirely across the press where there is keyed to it another crank 31 connected by a link 35 with an ear 33 on the eccentric at that side of the machine.

Yoke 38 carries the usual pins 9 and 4G and the usual extensions M and 42, the latter having adjustable abutment pins 43 that are adapted to engage a stop 44 fixed in the frame member l0. Pins 9 and 20 are adapted to be engaged by the shoulders on a thrust block Q5 pivoted at 46 on a lever t? which is pivotally mounted in the frame at it. d9 is a control rod pivotally connected with thrust block and adapted to be shifted longitudinally when the unit is to be tripped on or off. Lever 63 carries a follower 59 which runs on a cam 5i that is keyed to shaft [2.

A second follower 52 on a bell crank lever 53 also runs upon cam 5E. The other arm of lever 53 carries a pivot 5:3 upon which is mounted the rear end of a second thrust block 55. A crank 56 on lever All carries a wobble pin 5'! which is perforated to receive slidably a rod 53, the other end of which is pivoted to a crank 59 on lever 53. A compression spring 63 surrounding rod 58 bears at one end against wobble pin 57 and at the other against a collar iii on the rod, spring 60 thereby serving the double purpose of holding both of the followers Eii and 52 against the surface of cam 5i.

Thurst block 55 embodies the usual shoulders for engagement one at a time with pins 62 and 63 on a yoke 6t keyed to a shaft 65 which extends entirely across the machine. Yoke 64 also carries extensions cc and 57 with adjustable abutment pins 38 for engagement with a stop 69 fixed in the machine frame. A bifurcated crank 16 is integral with yoke 64 and carries an oscillatable pin H to which is secured a link '52, at the upper end of which there is an eye that is mounted upon a pivot is in the outer end of a crank arm "N that is keyed to a short shaft 55. Shaft 15 is journaled in an eccentric sleeve mounted in bracket I20 in the periphery of which sleeve are worm wheel teeth if. A worm i8 carried upon an upright shaft is journals-d in bracket E20 meshes with worm wheel teeth El and may be turned thereby for adjustment purposes; A gauge plate keyed to shaft it indicates the degree of adjustment. Parts numbered iii to 38 inclusive are duplicated on the opposite side of the machine, and the gauge plates assist materially in maintaining the adjustment equal.

The inner side of each of the eccentrics i5 is cut away as indicated at 8! in Fig. 4 to expose shaft '35, and that shaft is recessed to provide a curved socket 82 which receives one end of a link 83 shaped somewhat like a dumb-bell. The rounded extremity of the opposite end of this link bears against the wall of a curved recess 85 formed in the adjacent side of the bearing block IT. The center of shaft 15 is located at the point 85. The centers of curvature of the two extremities of link 83 are marked 86 and 8?. It will be observed that a toggle connection is thus set up with one arm 4- extending from point 85 to point 86 and the other arm extending from point 86 to point 8?. When the points 85, B6, 81 are in line, as in Fig. 1, the connection is on toggle. In practice the point 85 may be carried slightly above the line between points 85 and B1 to an over-center position for the sake of stability. The center of eccentric it is at 88. Obviously as the worm i8 is turned in one direction or the other the center 85 of shaft '15 moves inwardly or outwardly, and thus the outer extremity of the toggle connection is adjusted toward or away from the bearing block ll.

When the toggle is in toggle on position, as shown in Fig. 1, pressure is exerted against the bearing blocks I! along the line of centers between points 35 and El, which line cuts across the plane of the axes of cylinders l3 and It: at a point intermediate the axes of these cylinders which is disposed at a considerable distance from the axis of pin I9.

On the pin 40 carried by yoke 38 there is pivotally mounted a bracket 90 which has a bifurcated arm straddling pin 9. On this bracket there is an arm 91 to which is pivoted a rod s2 that extends through a sleeve 93 that is slidable upon the rod and is yieldably held in position by two coil springs 94 and 95 backed by collars 96 and 91 fixed to the rod. Lever 98 is mounted to turn upon a pivot 99 fixed in thrust block 55. Its opposite end is pivotally connected at N35 with sleeve 93.

Thrust block 55 carries a pair of integral projecting walls HM. An eccentric head its on one end of a shaft I03 fits between these walls. Head 592 bears against one surface of lever es and a collar [EM fixed to shaft I83 bears against the other surface of the lever. Two ears i6 5 and m5 extending laterally from the lever carry stop pins i5! and 108. Handle N39 is mounted in shaft H33 in a position to contact pin It! or itt at opposite extremes of its movement. Shaft use and handle its together may be termed a crank, by means of which eccentric I02 is turned to shift lever 93 on one or the other of the pivots 99 or iilfi as a can ter. Since the lever is connected with thrust block 55 by pivot 99, the swinging of lever as on pivot from one extreme position to the other in turn swings thrust block 55 upon its pivot 5 Operation-Assuming that the unit is in printing condition, as illustrated in Fig. 1, and that a throwoff of the unit is called for, control rod 158 will then be moved toward the right, which will swing thrust block 45 over into contact with pin t!) on yoke 33. When the high spot of cam 5i engages follower fiil, as in Fig. 2, a shoulder on thrust block 35 working against pin it will turn yoke 38 counterclockwise along withshaft breaking the toggle 31, 35 and turning the eccentrics 28 clockwise about their axis 29. The center of shaft- SI and of blanket cylinder 55 will thus be swung through a small fraction of an inch in a direction downwardly and toward the left. It will be understood that all of the cylinders 13, i i and I5 are provided with gears at the side of the machine not illustrated herein and that the gear on cylinder i5 meshes with the gears on both of the cylinders 13 and M. The gears remain in mesh when cylinder I5 is thus thrown oif from plate cylinder is, and since the relative movement of the gears on cylinders l5 and i4 is substantially tangential when the throwoff from cylinder is takes place, the contact between cylinders 15 and H3 is not affected.

When thrust block 45 swings from the position of Fig. 1 to that of Fig. 2 and turns yoke 38 and bracket 90 counterclockwise to the position of Fig. 2, rod 92 exerts a pull on lever 98 which is communicated through eccentric head I02 and pivot 99 to thrust block 55, swinging that block to the right as indicated in Fig. 2. When the high spot of cam 5| reaches follower 52, as shown in Fig. 3,v thrust block 55 is moved longitudinally toward the left, swinging yoke 64 and shaft 65 counterclockwise, which exerts a downward pull on each of the links I2 and functions through cranks 14 to turn shafts l5 clockwise, thereby breaking each of the toggle connections of which dumb-bell link 83 is one arm. With the breaking of the toggle connections springs 24 act to swing bearing blocks I'I upon pins I9 as pivots. The center of shaft 3I therefore swings away from cylinder I4 a small fraction of an inch. In this case the relative travel of the gears on cylinders I3 and I5 is substantially tangential, and is easily permitted by the fact that they are then meshing loosely due to their previous separation. These two motions of cylinder I5 in the throwoff first from cylinder I3 and then from cylinder I4 occur in the same cycle of the press. The throwoif from the plate cylinder occurs while gaps G and G of the plate and blanket cylinders are passing each other, the throwoif having been completed at the time in the cycle depicted in Fig. 2. The throwofi from he impression cylinder l4 occurs while the gaps G of the blanket cylinder and G of the impression cylinder are passing each other, having been completed at the point illustrated in Fig.

The printing of a sheet passing the impression line between cylinders I5 and I4 is completed after the throwofi from cylinder I3 and before the throwoif from cylinder I4.

When the feeding of sheets is resumed after a short interruption, control rod 49 is moved toward the left from the Fig. 3 position to the Fig. '1 position, causing the yoke 38 to turn clockwise and the toggle connections 31, 35 to assume the on toggle position of Fig. 1, which turns eccentrics 2B counterclockwise for throwing the blanket cylinder into printing engagement with plate. cylinder I3. At the same time that yoke 33 turns clockwise rod 92 is pushed down and toward the left, operating through lever 98 and eccentric head I02 to swing thrust block 55 toward the left into the position of Fig. 1, where it is ready to be acted upon by cam 5| for turning yoke 64 clockwise from the Fig. 3 position to that of Fig. 1. Thismotion of yoke 64 is transmitted through crank and link I2 to crank M, shifting the toggle connection center 86 up into line with the centers 85 and 81 to bring the parts of the toggle connection to the on toggle position against the action of compression spring 24, thereby throwing the blanket cylinder into operative engagement with the impression cylinder. x

When the toggle 35, 31 is put into toggle-on position, as illustrated in Fig. 1, for throwing the blanket cylinder I5 into operative position with respect to plate cylinder I3, the reaction from the force necessary to press cylinder I5 upwardly against cylinder I3 is taken largely by the bearing block pins I9. Consequently there is friction of rest between the pins and the bearing caps 2|, which must be overcome in shifting the cylinder I5 sequentially into printing relation with impression cylinder I4. The means disclosed herein for overcoming this friction and pressing the cylinder I5 against the cylinder I4 or the paper passing between these 75 cylinders possesses considerable mechanical advantage. In the first place there is mechanical advantage in the length of lever arm '14 as compared with the short arm of the toggle, namely that between points 85 and 86, and in the second place there is the mechanical advantage gained from the length of the arm between the axis of pivots I9 and the point at which force is applied to the bearing blocks I! as compared with the radius of pivots I9.

While as shown herein the pivots I9 are so disposed as to provide for the swinging of the bearing blocks toward or away from the impression cylinder, it will be appreciated that the pivots could be so disposed as to provide for swinging the bearing blocks toward or away from the plate cylinder, the eccentrics 28 then functioning to move the blanket cylinder toward or away from the impression cylinder.

When a run of printing is to be started or is to be resumed after a period of idleness, it is necessary to ink up the blanket by several passes over the form on cylinder I3 before sheets are fed through the impression line between cylinders I4- and I5. For this purpose it should be possible to throw the blanket cylinder onto the plate cylinder while separation of the blanket cylinder from the impression cylinder is maintained. This is accomplished in the present invention by the mechanism illustrated in detail in Figs. 6, 7 and 8. When it is desired to start the unit'under these conditions, the handle I09 is thrown from the position illustrated in Figs. 1, 2 and 3 to the position illustrated in Fig. 6. The eccentric head IE2 is thus turned through slightly more than 180 degrees. Since the thrust block 55 bears at this time against pin 63 and pivot 99 is fixed in the thrust block the turning of eccentric head I02 cannot move pivot 99 bodily. Consequently the opposite end of the lever 98 must yield, and this results in sliding the sleeve 93 on rod 92 toward the left, compressing spring 94. Now the operator causes control rod 49 to move toward the left, throwing thrust block against pin 9, whereupon cam 5| operates through follower 59, bell crank 41 and thrust block 45 to swing yoke 39 clockwise and bring the toggle 37, 35 to on toggle position for throwing the blanket cylinder onto plate cylinder I3. As yoke 38 turns clockwise rod 92 is forced downwardly and toward the left, thereby moving collar 96 away from sleeve 93 and reducing the compression of spring 94 somewhat. This downward movement of rod 92 is not sufiicient to move thrust block from its Fig. 3 position however and therefore the toggle connection which includes dumb bell link 83 remains in the off toggle position and the blanket cylinder is not thrown over into engagement with impression cylinder i 4.

When the blanket is properly inked the operator, who has meanwhile been manually holding control rod 49 toward the left in the impression on position, releases the latter rod so that cam 5| operates through lever 47 and thrust block 45 to swing yoke 38 counterclockwise and throw blanket cylinder I5 away from plate cylinder I3. The counterclockwise movement of yoke 38 moves rod 92 to the right to the position shown in Fig. 3, increasing the compression of spring 94. Thereafter the operator throws handle I09 back to the position illustrated in Figs. 1, 2 and 3 which causes lever 98 to swing about pivot 99 and move sleeve 93 toward the right to its normal position in which the springs 94 and 95 are free to swing the thrust block to either of its operative posi- 7 tions under the control of rod 92. When normal conditions are thus restored, the feeding of sheets may be started and the pressure between the cylinders thrown on or off in sequence in the manner described under the control of rod 49.

Having thus described my invention, I claim? 1. In a rotary offset printing press, a frame, a printing unit comprising a plate cylinder, an impression cylinder and a blanket cylinder, said blanket cylinder having a shaft the axis of which is disposed to one side of the plane through the axes of the plate and impression cylinders, a pair of like bearing blocks movably mounted in said frame at the opposite ends of the blanket cylinder, a pair of like eccentrics rotatably mounted in said bearing blocks, said blanket cylinder shaft being mounted in said eccentrics, a cam rotating once for each press cycle, mechanism operatively associated with said cam for turning said eccentrics, a control settable for causing said cam to actuate said mechanism to impression ofi position, a second mechanism operatively associated with said cam for moving said bearing blocks, and a control responsive to actuation of said first mechanism to impression ofi position for setting said second mechanism in position to be actuated by said cam later in the cycle for moving said bearing blocks to impression oil" position.

2. In a rotary ofiset printing press, a frame, a printing unit comprising a plate cylinder, an imression cylinder and a blanket cylinder, said blanket cylinder having a shaft the axis of which is disposed to one side or" the plane through the axes of the plate and impression cylinders, a pair of like hearing blocks at the opposite ends of the blanket cylinder, mounted in said frame to swing about a common axis parallelwith the axis of the blanket cylinder, a pair of like eccentrics rotatably mounted in said pair of bearing blocks, said blanket cylinder shaft being mounted in said eccentrics, a cam rotating once for each press cycle, mechanism operatively associated with said cam for turning said eccentrics, a control settable for causing said cam to actuate said mechanism to impression oii position, a second mechanism operatively associated with said cam for swinging said bearing blocks, and a control responsive to actuation of said first mechanism to impression oil position for setting said second mechanism in position to be actuated by said cam later in the cycle for swinging said bearing blocks to impression off position.

3. Mechanism as defined in claim 2, characterized in that during operation of the press the common axis of said bearing blocks is disposed approximately inthe same plane with the axes blanket cylinder having a shaft the axis of which disposed to one side of the plane through the of the plate and impression cylinders, a pair of like bearing blocks at the opposite ends of the blanket cylinder mounted in said frame to swing together about a common axis parallel with the axis of the blanket cylinder, a pair or like eccentrics rotatably mounted for movement together in said pair of bearing blocks, said blanket cylinder shaft being mounted in said eccentrics, mechanism for turning said eccentrics comprising a pivoted yoke, a crank integral therewith and a thrust block swingable into operative relation with either end of said yoke, and a link pivotally connected with said crank and one of said eccentrics, mechanism for swinging said bearing blocks comprising a pivoted yoke, a crank integral therewith and a thrust block swingable into operative relation with either end of said yoke, and an operative connection between said crank and one of said bearing blocks, a connection between the first named yoke and the second named thrust block for swinging the latter from one operative position to the other, and cam means for reciprocating said thrust blocks one at a time, whereby the turning of said eccentrics results in the setting of the thrust block for swinging said bearing blocks.

6. In a press unit of the character described, a pivoted thrust block having two operative positions angularly separated, a lever, a pivot connecting one end of said lever with said thrust block, a crank oscillatably mounted in said lever at an intermediate point of the latter, an eccentric head connection between said crank and said thrust block, and a reciprocable operating rod, a sleeve slidable thereon articulated with the opposite end of said lever, springs on said rod bearing against the opposite ends of said sleeve, the endwise movement of said rod being normally adapted to shift said block from one operative position to the other, the turning of said crank to move said eccentric head through a predetermined angle swinging said lever about its pivot and shifting said slide to increase the pressure of one of said springs and decrease that of the other, whereby movement of the rod thereafter in one direction merely equalizes the spring pressure and leaves the thrust block unafiected.

Mechanism as defined in claim 6, comprising a pair of stops on said lever to limit the throw of said crank in opposite directions.

8. in a press unit of the character described, a pivoted thrust block member having two operative positions angularly separated, a lever memher, a pivot connecting said lever member with thrust block member, a crank oscillatably mounted in one of said members, an eccentric head on said crank engaging abutments on the other of said members, a reciprocable rod, a sleeve slidable thereon, springs on the rod bearagainst opposite ends of said sleeve, the endwise movement of the rod being adapted when said crank is in one position to shift the thrust block from one operative position to the other, the movement of said crank to its opposite position shifting said sleeve to increase the pressure of one of said springs and decrease that of the ether, whereby the movement of said rod thereafter in one direction affects merely the presssure oi said springs and leaves said thrust block unaiiected.

9. In a press unit of the character described, a ivoted thrust block having two operative posins angularly separated, an operating rod movz; e lengthwise transversely of the block and parallel to the plane in which it is adapted to swing, a sleeve slidable on said rod, compression springs on said rod bearing against opposite ends of said sl eve tending to hold said sleeve in a predetermined position on said rod, a lever having an articulated connection with said sleeve, a pivot means for swinging said lever on its pivot to shift said sleeve for compressing one of said springs, whereby when the thrust block is held against movement in one direction the actuation of said operating rod in the opposite direction merely relieves the compression of said last named spring and transmits no motion to said thrust block.

10. In a press unit of the character described, a pivoted thrust block having two operative positions angularly separated, a lever, a pivot connecting said lever with said thrust block, a reciprocable operating rod adapted to shift said block from one operative position to the other, a sleeve slidable thereupon, compression springs on said rod bearing against opposite ends of said sleeve tending to hold said sleeve in a predetermined position on said rod, an articulated connection between said sleeve and one end of said lever, means for swinging said lever on its pivot to shift said sleeve for compressing one of said springs and a stop adapted to prevent movement of the thrust block in one direction, movement of said rod thereafter in a direction tending to move the thrust block away from said stop results merely in relieving the compression of said last named spring.

11. In a rotary offset printing press, a frame, a printing unit comprising a blanket cylinder and plate and impression cylinders cooperating therewith, said blanket cylinder having a shaft the axis of which is disposed to one side of the plane through the axes of said cooperating cylinders, a pair of bearing blocks at the opposite ends of the blanket cylinder, in which the cylinder shaft is mounted, openings in the frame of a size to clear said blocks, aligned pivots parallel to the cylinder shaft spaced radially from said shaft upon which said blocks are mounted to swing bodily to throw said blanket cylinder toward or away from one of said cooperating cylinders and removable means for holding said blocks against movement axially of said pivots, whereby upon release of said last named means one of said blocks may be moved outwardly through the opening in that side of the frame.

12. In a rotary offset printing press, a frame, a printing unit comprising a blanket cylinder and plate and impression cylinders cooperating therewith, said blanket cylinder having a shaft the axis of which is disposed tov one side of the plane through the axes of said cooperating'cylinders, a pair of like bearing blocks at the opposite ends of the blanket cylinder, bearings for the blanket cylinder shaft in said blocks, openings in the frame of a size to clear said blocks, aligned pivots parallel to the cylinder shaft spaced radially from said shaft upon which said blocks are mounted to swing bodily to throw said blanket cylinder toward or away from one of said cooperating cylinders and removable means for holding said blocks against movement axially of said pivots, whereby upon release of said last named means one of said blocks with its shaft bearing may be moved outwardly through the opening in that side of the frame. 7

13. In a rotary offset printing press, a frame, a printing unit comprising a blanket cylinder and plate and impression cylinders cooperating therewith, said blanket cylinder having a shaft the axis of which is disposed to one side of the plane through the axes of said cooperating cylinders, a pair of like bearing blocks at the opposite ends of the blanket cylinder, aligned pivots for said bearing blocks carried by said frame, a pair of like eccentrics rotatably mounted in said bearing blocks, said blanket cylinder shaft being mounted in said eccentrics, means for turning said eccentrics to throw said blanket cylinder into printing relation with said last named cooperating cylinder, means for applying pressure to said blocks for swinging said blanket cylinder about said pivots into printing relation with the other of said cooperating cylinders, said frame being provided with openings for said blocks such that the blocks may be removed from the blanket cylinder shaft by a movement along the axis of said shaft, and removable means for holding said blocks against movement axially of said pivots.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,107,843 Robertson 1 Aug. 18, 1914 1,988,970 Hotchkiss Jan. 22, 1935 2,079,001 Crafts l May 4, 1937 2,356,058 Hunting Aug. 15, 1944 

